Validation of the Brazilian Portuguese version of the Quick Inventory of Depressive Symptomatology and Self-Report (QIDS-SR16) for the Brazilian population

Abstract Objectives To evaluate the psychometric properties of the Quick Inventory of Depressive Symptomatology (QID-SR16), a self-report instrument based on the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria that assesses the severity of depression symptoms, in the Brazilian population. Methods Participants were 4,400 Brazilians over the age of 15 years recruited for an online survey assessing depressive symptoms during the early phase of the coronavirus disease 2019 (COVID-19) pandemic in Brazil. The internal consistency, construct validity, and convergent and discriminant validity of the QIDS-SR16 were evaluated. Results The model tested was considered an adequate fit to the data (comparative fit index [CFI] = 0.947, Tucker-Lewis index [TLI] = 0.927, and root-mean-square error of approximation [RMSEA] = 0.051) and its internal consistency was good, with a Cronbach’s alpha of 0.71 and an average item correlation of 0.23. The correlations between the total QIDS-SR16 score and the total scores of the Patient Health Questionnaire (PHQ-9) instruments (r = 0.67, p < 0.001), the Posttraumatic Symptoms Checklist (PCL-5) (r = 0.61, p < 0.001), and the Patient-Reported Outcomes Measurement Information System (PROMIS) (r = 0.60, p < 0.001) indicate good concurrent and convergent validity. Conclusion The QIDS-SR16 has robust psychometric properties in terms of its internal consistency, construct validity, and convergent and discriminant validity. The Portuguese version of the QIDS-SR16 is an adequate instrument for assessment of depressive symptoms in the context of an online survey.


Introduction
In 2020, the World Health Organization (WHO) estimated that depression was the second leading cause of disability in the world and it is responsible for significant impairment of people's functionality and quality of life. 1 It is a serious disorder, with incidence that increases year on year, and is associated with considerable morbidity and increased mortality in the general population. 2,3 There are 322 million people living with depression in the world and it is more common among women (5.1%) than among men (3.6%)WHO, 4 In Brazil, there are few population-based studies to precisely estimate the prevalence of depression. However, a national study with approximately 3,000 participants found that the prevalence of depressive symptoms was 28.3% of participants, with 15.3% of them occurring in depressive episodes considered severe. 5 The severity of depressive symptoms is an important factor to consider in initial assessments, requiring use of brief and effective instruments that provide the health professional with this data, since treatment guidelines can be established on the basis of this information, leading to greater effectiveness. 6 Several of these assessments are made in primary care settings, which is often where the population first accesses and comes into contact with health professionals, and an estimated 19.5% of depression cases are diagnosed at this level of care. 7 13

and the Hamilton Depression
Rating Scale (HAM-D6), 14 but they usually require trained professionals and are time consuming. Thus, the Quick Inventory of Depressive Symptomatology and Self-Report (QIDS-SR 16 ), derived from the Inventory of Depressive Symptomatology-Self-Report (IDS-SR 30 ), 15 emerges as an option to enable initial assessment of depressive symptoms to be conducted quickly and efficiently, since it focuses only on the nine criteria necessary for a diagnosis of major depressive disorder contained in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), and is easy for the general population to understand.
In addition, the QIDS-SR 16 seems to offer some advantages in relation to the other scales. When compared with the CES-D and the DASS, it has a closer relationship with the DSM criteria for depression, greater sensitivity to change, and better assessment of the risk of suicide. 16 A study comparing the sensitivity and specificity of scales for depression in primary care observed that the QIDS-SR 16 had greater specificity for assessment of major depression and minor depression than the PHQ-9 (84.7% vs. 72.2%). 17 The HADS may be an appropriate scale for assessment of depressive symptoms, but it ends up excluding the disorder' somatic symptoms, suppressing a dimension that can be important in this initial assessment and which is covered by QIDS-SR 16 . 18 The BDI-II is one of the main instruments for evaluation of depression and has good correlations with the QIDS-SR 16 . 19 However, in Brazil it is too expensive for use as a tool for initial screening in primary health care settings. In addition, it must be considered that, according to our legislation (Resolução CFP 009/2018), the BDI-II can only be used by experienced psychology professionals, who are not always available at primary care units.
The QIDS-SR 16  weight, and 9) psychomotor agitation/retardation. 19 Each item can be scored on a response scale from 0 to 3, on which respondents choose the score that best describes them in the last 7 days. The QIDS-SR 16 total score ranges from 0 to 27, with higher values indicating greater severity of depressive symptoms.
Thus, QIDS-SR 16 constitutes an important screening tool to identify primary care patients who may meet the diagnostic criteria for major depressive disorder 20 that is easier for health professionals to use, 21 since it requires minimal training for application because it is a self-administrated instrument. 19 However, considering that no validation studies exist for the Brazilian population, this study aims to evaluate the psychometric properties of construct validity, internal consistency, and concurrent and convergent validity of the Brazilian Portuguese version of the QIDS-SR 16 scale.

Data collection
This is a cross-sectional and observational study. openepi.com), adopting a 95% confidence level, a 1% margin of error, and a random sample. A set of criteria was applied to maximize data reliability.
Initially, participants who took less than 5 minutes to complete the survey were excluded. Then, with regard to socioeconomic variables, participants who provided invalid information about age, zip code, and the last four digits of their mobile numbers were excluded (only the last four digits were requested to avoid identifying participants). Subsequently, since in this study we were not interested in investigating changes that occurred in participants over time, possible repeated measures were excluded by checking for both repeated zip codes and the last four cellphone digits.

Instruments
Quick Inventory of Depressive Symptomatology-Self-

Report (QIDS-SR16)
The QIDS-SR 16 is a brief scale for assessing depressive symptoms based on the DSM-IV diagnostic criteria that is derived from the IDS-SR 30 scale, originally developed in English. The IDS-SR 30 was adapted to Brazilian Portuguese, exhibiting good psychometric properties. 22 The QIDS-SR 16

Construct validity
A single-factor model of depressive symptoms composed of all nine symptoms measured by QIDS-SR 16 ( Figure 1) was tested with confirmatory factor analysis using full maximum information likelihood estimation.
The model tested was considered adequate to the data according to the indexes χ² (26, n = 4,400) = 325.376, p < 0.001, CFI = 0.947, TLI = 0.927, and RMSEA = 0.051. More information about the item factor loadings is presented in Table 2.

Internal consistency
The QIDS-SR 16 demonstrated good internal consistency with a Cronbach's alpha of 0.71 and an average correlation coefficient between items of 0.23.

Discussion
The original study that developed and validated the QIDS-SR 16 demonstrated its usefulness for evaluation of depressive symptoms and proved its psychometric validity. 15 This instrument has been tested in a variety of settings for assessment of depressive symptoms, such as for assessment of young adult students at universities, 33 in veteran military personnel with comorbid post-traumatic stress disorder, 34 and in patients with bipolar mood disorder. 35 Its usefulness for screening for depressive symptoms in primary health care is emphasized 13,17,20,36 and it can be an important instrument within this context.
In this study, we sought to validate the Brazilian translation of the QIDS-SR 16  German (0.77), 38 and Korean (0.73) versions. 39 The differences in these values in relation to the original version and to the other versions cited can be explained by the sample size used in each of the translation validation processes. In our study, we had a total of 4,400 respondents, which is a much larger number than in the validation process for the original version (n = 596) 19 and also than in the other validation studies. We also emphasize that our study analyzed a symptomatic population in the context of the pandemic, since people were directed to fill out the QIDS-SR 16 after an initial screening using the PHQ-9 scale, which differs from the other validation studies of the scale. 19,40,41 We could infer that the fact that the collection took place online and not face-to-face as in the other translation validation processes could interfere with our results, although several studies have shown that there are no significant differences in the quality of the data collected when administration via these two modalities is compared. Moreover, online research may even be more advantageous, because in theory it allows for more sincere responses from participants. 42,43 All of the correlations between the total QIDS-SR 16  issue is that 83% of the participants were female, which makes it more difficult to generalize these data for both sexes. However, it is observed that there is an important sex-difference in rates of depression diagnosis, with a higher prevalence in women than in men. 44 Considering the high incidence of diagnoses of depressive conditions in Brazil in primary care outpatient clinics 8 and the adequacy of the psychometric properties of the Brazilian Portuguese translation of QIDS-SR 16 , it is concluded that this instrument may be able to assist health teams in assessment of and screening for depressive symptoms, without requiring minimal preparation for this, since it is not always possible to count on the presence of a mental health professional in this health care sector.